1. Field of the Invention
The embodiments of the invention relate to an impact tool for a hammer device that can be used axially in both directions, in particular an impact tool for a hammer drill for opening and optionally for closing a tapping opening of a metallurgical vessel. The impact tool includes a tubular piston that is displaceable in the axial direction by a pressure medium in an impact tool housing. A central or proximal adjustable transfer part of the impact energy connectable to at least one tool and having anvil parts on both sides is also included, as is a device for reversing the direction of the pressure applied to the tubular piston. The tubular piston has essentially radial pressure surfaces on both sides that can be acted on with a pressure medium, and grooves between the tubular piston and the impact tool housing for reversal of a direction of pressure medium impingement on the pressure surfaces and discharge or recirculation of the medium.
Furthermore, embodiments of the invention relate to a method for opening or closing a tapping opening in a wall of a metallurgical vessel provided with a fireproof infeed.
2. Discussion of Background Information
Hammers that can be operated pneumatically or hydraulically with an impact tool, which has tubular pistons that can be acted on respectively axially on both sides with pressure medium are prior art and disclosed, for example, in EP 0 930 476 B1, the disclosure of which is expressly incorporated by reference herein in its entirety. Impact tools of this type are preferably used for devices that cause an advancement or withdrawal of a tool in both directions, such as device for opening and closing tapping openings of metallurgical vessels and the like.
A regulation within limits of the impact energy as well as the impact frequency of the tubular piston can be carried out in a complex manner by conversions of the hammer device or by an adjustment of the quantity per time unit and/or of the pressure of the fed pressure medium.
In the case of metallurgical vessels, such as blast furnaces and the like, it can be favorable to provide a high impact frequency and a low impact force of the tool for opening the taphole in the wall.
When drawing the drilling tool out of the taphole after the penetration in order to prevent a jamming of the same, it is respectively advantageous in terms of process engineering to apply a highest possible backlash force also with lower impact frequency.